血管参数对皮肤组织选择性光热解作用中光热响应规律的影响

利朋选择性光热解(SP)的三维光热作用模型,对血管尺寸、位置和数目等血管参数对皮肤组织选择性光热解作用中光热响应规律的影响进行了理论分析和数值求解.数值结果表明,当利用选择性光热解效应热损伤皮肤组织内的特定血管时,假如一定区域内有其他血管存在,则目标血管的热损伤率会受区域内其他血管的影响而减小.这个区域的大小与激光光斑大小及激光波长有关.一般来说,当血管处于激光光斑以外或深度超过1 mm(对于585 nm激光)时,这些血管的影响可忽略不计.     

光子嫩肤术的作用机制

通过分析激光或非激光辅射的波长、曝光时间和曝光剂量等参数的物理意义，唯象地诠释了光子嫩肤术的作用机制．指出光子嫩肤是基于光辐射与皮肤组织间产生的光热解效应。     

超快脉冲激光对黑素细胞作用及机制

Ａｎｄｅｒｓｏｎ(1983)在Ｓｃｉｅｎｃｅ提出选择性光热分解理论 ,人们第一次针对皮肤疾病特点而设计用超快脉冲激光 (脉冲宽度为ｎｓ量级 )医用仪器治疗皮肤色素沉着性疾病 ,取得了丰硕的成果。黑素细胞是皮肤唯一能合成黑色素的细胞 ,并参与皮肤的免疫反应和光老化的过程 ,     

激光自混合干涉位移测量系统的稳态解

近年来,关于激光自混合效应及其应用有很多报道,我们已对弱光反馈水平下和较高反馈水平下自混合效应作了研究,并研究了利用该效应进行位移测量的技术.本文则针对激光自混合干涉位移测量系统的稳态解,进行分析,从理论上确定系统稳态运行条件. 本文通过求解所建立的激光自混合干涉位移测量系统模型的相位方程,确定其单值解和多值解时边界条件,经稳态模分析,确定系统稳态运行的参数选择规则.该结论提供了系统设计准则.(OE26)     

用于激光热疗的激光抽运高掺杂光纤光热头研究

利用晶体光纤中高掺杂离子的非辐射跃迁机制,研制成功一种可用于激光热疗的高掺杂光纤光热转换头。在一个809nm半导体激光器抽运下,光热头在空气和蛋清样品中分别产生最高达465℃(抽运功率为1124mW)和98℃(抽运功率为933mW)的温度,已足够用于激光热疗。同时,光热头在温度稳定性、热响应时间、生物相容性、抗热冲击强度和化学稳定性等方面均能满足要求。     

激光多普勒测速实验系统

利用激光多普勒效应测量流体流速已成为近年来测速系统的发展趋势,激光多普勒测速具有高精度、非接触等优点,但由于激光器的限制此技术尚未广泛普及应用。详细推导了多普勒测速的原理和计算方法,相信能够为解决实际问题带来帮助,例如暖气管道流量计的设计等。     

激光与皮肤层状组织的光热作用及其传热模型

本文基于激光与生物组织相互作用的机理,对激光与组织光热相互作用形成的热源项进行拓宽理解,并分析了激光照射下组织光热性质的关联。在此基础上,提出了激光与皮肤层状组织相互作用传热模型。数值模拟获得的若干结果与相关文献的报道一致,方法为精确预测激光诱发的组织热响应提供有力的工具。     

激光辐照皮肤组织的光子传输解析计算研究

建立了激光与皮肤组织相互作用的二维非稳态光场模型,在柱坐标系下采用漫射近似法和格林函数法精确求解了高斯和平顶分布的连续激光辐照皮肤组织的光传输方程,得到瞬态光场分布,并以氦氖激光辐照皮肤组织为例,数值模拟了皮肤组织在激光作用下的光分布。研究结果表明：皮肤组织径向光分布规律与入射激光束的光强分布相似,激光与组织光效应在很大程度上取决于激光参数,主要有激光功率、焦斑半径等。     

激光在光度分析中的应用

本文综述了激光在光度分析中的应用现状,重点介绍了激光诱导荧光光谱分析法、激光光声光谱分析法、激光光热光谱分析法、激光腔内吸收光谱法和半导体激光器在光度分析中应用的新进展。     

CO2激光热处理光热转换层的应用分析

介绍了CO_2激光热处理光热转换层技术,分析了磷化法和喷涂法工艺生成的光热转换层在激光热处理中的特点。针对磷化法光热转换层的热稳定性差、温度升高吸收率下降、磷酸盐溶液的污染等缺陷,探讨了喷涂法光热转换层作为激光热处理预处理层的应用,可显著地提高激光热处理的效率。     

Towards a theory of application in systems science

The actual utilization of systems science, especially social systems engineering, has not measured up to the plethora of theories and examples of potential applications in the literature. To begin developing a theory of application in systems science, one may consider modeling the systems scientist as a system or consider nonsystems approaches that would include the political influence, feelings, aesthetic, and religious dimensions of both the analyst and the user. The essential ideas of this process are presented in summary form.     

A low fluence Q-switched Nd:YAG laser modifies the 3D structure of melanocyte and ultrastructure of melanosome by subcellular-selective photothermolysis

Laser treatment using low fluence for melasma was previously introduced to overcome postinflammatory hypermelanosis after Q-switched laser therapy. However, research on the mechanism of this treatment is very limited. In this study, a collimated low fluence 1064?nm Q-switched Nd:YAG laser with a pulse width of <7?ns was applied using top-hat beam mode. The aim of this study was to investigate the mode of action of this laser treatment through electron microscopy. The effectiveness of this treatment was confirmed by clinical photos, melasma area and severity index and spectrophotometer. To understand the mode of action, the three-dimensional structure of melanocytes in the epidermis was analyzed using serial images acquired by a 3VIEW surface block face scanning electron microscope. In the epidermis, after laser treatment, fewer dendrites in the melanocytes were observed compared with pretreatment. In addition, ultrastructural changes in the melanosome were studied using transmission electron microscopy, which showed that laser treatment caused selective photothermolysis on Stage IV melanosome. Therefore, this treatment should be regarded as an effective method for treating melasma through subcellular-selective photothermolysis.     

Virtual surgery in a (tele-)radiology framework

Presents telemedicine as an extension of a teleradiology framework through tools for virtual surgery. To classify the described methods and applications, the research field of virtual reality (VR) is broadly reviewed. Differences with respect to technical equipment, methodological requirements and areas of application are pointed out. VR, desktop VR and augmented reality are differentiated and discussed in some typical contexts of diagnostic support, surgical planning, therapeutic procedures, simulation and training. Visualization techniques are compared as a prerequisite for VR and assigned to distinct levels of immersion. The advantage of a hybrid visualization kernel is emphasized with respect to the desktop VR applications that are subsequently shown. Moreover, software design aspects are considered by outlining functional openness in the architecture of the host system. A teleradiology workstation was extended by dedicated tools for surgical planning through a plug-in mechanism. Examples of recent areas of application are introduced, such as liver tumor resection planning, diagnostic support in heart surgery, and craniofacial surgery planning. In the future, surgical planning systems will become more important. They will benefit from improvements in image acquisition and communication, new image processing approaches and techniques for data presentation. This will facilitate pre-operative planning and intra-operative applications     

Effects of time selective multipath fading on OFDM systems forbroadband mobile applications

The effects of time selective multipath fading are investigated for orthogonal frequency-division multiplexing (OFDM) systems in broadband mobile applications. Although in a multipath environment an OFDM system is very robust against frequency selective fading, it is very sensitive to time selective fading characteristics of the mobile channel, causing inter-carrier-interference and degrading system performance. To achieve a signal-to-interference ratio of 20 dB, the OFDM symbol duration must be less than 8% of the channel coherence time     

Stored program control-assisted electromechanical switching—An overview

This article provides an overview of localized stored program control applications in existing electromechanical switching systems. Economic factors and design constraints imposed by established system architectures are reviewed. Criteria for introducing stored program control, along with main design considerations for its implementation, are outlined. Examples are given of actual electro-mechanical switching systems that have been modernized with selective application of stored. program control to upgrade system features and capabilities.     

等离子体选择性隐身技术在未来陆军装备的应用分析

等离子体隐身技术逐渐从实验室走向实用化,并且从航空领域的应用向航海舰船隐身以及地面武器装备隐身的方向拓展。本文首先介绍等离子体隐身的基本原理,然后,讨论等离子选择性隐身技术在未来陆军装备的应用所面临的技术难题,最后,提出未来陆军武器装备多层次多频谱隐身的设想。     

Applications of lasers to biology and medicine

The applications of lasers to medicine and biology have grown very rapidly over the last decade and now include a wide variety of activities. These range from eye surgery through holographic microscopy and pattern recognition to the sealing of dental enamel. This paper reviews some of the fundamentals which underlie these applications and briefly reviews a few of the more significant applications themselves. In particular, the interactions between lasers and the biological material are discussed in an attempt to develop a physical foundation for the applications of lasers to surgery. This is followed by a discussion of the threshold for laser damage to eyes and the application to the repair of detached retinas and diabetic retinopathy. Applications of lasers to more general surgery, such as cutting of the liver, and to the special problem of microsurgery in embryology, are treated briefly. A variety of other papers and books have treated some aspects of this subject [1]-[5]; however, this paper presents a concise treatment of major applications with more than usual emphasis on the background physics. The background on holographic microscopy and pattern recognition is not treated here, but is partially covered in [6]-[9].     

Enzyme Mimics for Engineered Biomimetic Cascade Nanoreactors: Mechanism,Applications, and Prospects

Multiple enzyme-driven biological catalytic cascades occur in living organisms, guiding highly efficient and selective transformations of substrates. Inspired by the merits of these biological catalytic cascade systems, enormous efforts have been devoted to developing novel cascade catalytic systems to mimic biological cascade catalytic reactions over the past few years. Nanozymes, a class of enzyme mimics, are nanomaterials with enzyme-like catalytic activity. The emergence and development of nanozymes has significantly advanced the development of biomimetic cascade nanoreactors. Currently, biomimetic cascade nanoreactors driven by advanced nanozymes have been widely used and exhibit many advantages such as superior cascade catalytic efficiency and high stability, resulting in significant advancements in biosensing and biomedical applications. The latest advances in understanding the cascade catalytic mechanism of nanozyme-engineered biomimetic cascade catalytic nanoreactors and their progressive applications for biosensing and biomedical applications are comprehensively covered here. First, nanozyme and enzyme/nanozyme-engineered biomimetic cascade catalytic nanoreactors are categorized according to their catalytic mechanism and properties. Then, the biosensing and biomedical applications, including cancer therapy, antibacterial activity, antioxidation, and hyperuricemia therapy of the cascade catalytic systems are covered. The conclusion describes the most important challenges and opportunities remaining in this exciting area of research.     

Recent Advances of Cell Membrane‐Coated Nanomaterials for Biomedical Applications

Surface modification of nanomaterials is essential for their biomedical applications owing to their passive immune clearance and damage to reticuloendothelial systems. Recently, a cell membrane‐coating technology has been proposed as an ideal approach to modify nanomaterials owing to its facile functionalized process and good biocompatibility for improving performances of synthetic nanomaterials. Here, recent advances of cell membrane‐coated nanomaterials are reviewed based on the main biological functions of the cell membrane in living cells. An overview of the cell membrane is introduced to understand its functions and potential applications. Then, the applications of cell membrane‐coated nanomaterials based on the functions of the cell membrane are summarized, including physical barrier with selective permeability and cellular communication via information transmission and reception processes. Finally, perspectives of biomedical applications and challenges about cell membrane‐coated nanomaterials are discussed.